Roll system for continuous casting machines

ABSTRACT

A roll system for withdrawal of the casting in a continuous casting machine is disclosed, providing for particular distribution of power driven rolls and idlers along the withdrawal path.

United States Patent Vogt et al.

[ 1 Feb. 29, 1972 [54] ROLL SYSTEM FOR CONTINUOUS CASTING MACHINES [72] Inventors: Gerd Vogt, Schuerkesfeld; Hans Schrewe,

Duisburg-Ungelsheim, both of Germany [73] Assignee: Mannesmann Aktiengesellschaft, Duesseldorf, Germany 22 Filed: Jan. 14, 1970 21 Appl.No.: 2,918

[30] Foreign Application Priority Data Jan. 21, 1969 Germany ..P 19 03 426.5

[52] US. Cl ..l64/282 [51] Int.Cl ..B22d 11/12 [58] Field of Search ..164/82, 282, 283

[56] References Cited UNITED STATES PATENTS 3,324,931 6/1967 Bungeroth et a1 ..164/282 X 3,329,199 7/1967 Easton ..164/282 X 3,372,731 3/1968 Pauels et al.. "164/82 3,566,951 3/1971 Schrewe 164/82 FOREIGN PATENTS OR APPLICATIONS 719,065 1 1/1954 Great Britain 164/82 900,734 7/1962 GreatBritain ..l64/282 Primary Examiner-R. Spencer Annear AttorneySmyth, Roston & Pavitt [57] ABSTRACT A roll system for withdrawal of the casting in a continuous casting machine is disclosed, providing for particular distribution of power driven rolls and idlers along the withdrawal path.

8 Claims, 1 Drawing Figure ROLL SYSTEM FOR CONTINUOUS CASTING MACHINES The present invention relates to a roll system for withdrawing and guiding the casting leaving a curved mold or die of continuous casting equipment, whereby rolls are provided in a level or levels where the casting is only partially solidified. These rolls are arranged particularly on opposite sides in relation to the curved path of the casting, some of these rolls being idlers, others being driven.

It is known to provide rolls for guiding the extracted casting and which bear against the casting to prevent its bulging. For

this, all or some of these guide rolls are being driven. The invention now relates to the specific problem, to arrange the driven rolls guiding that portion of the casting which has still a liquidous core, and along a curved path so that the solidified shell of the casting is very little subjected to stress particularly by and within the arrangement of rolls. Moreover, it is assumed, that bending points are included along that path for veering the casting, for example, from a curved, downward oriented withdrawal path into a horizontal path whereby the curved casting is straightened.

In accordance with the invention, it is suggested that above the first bending point of the withdrawal, extraction and guiding path of the casting only one or two rolls are driven, and they are arranged on the inside of the curved path. Furthermore, in advance of every bending point of the curved path, and again on the inside thereof, one or two driven rolls are to be provided.

For moving the elongated casting and behind the first bending stage, the casting is drawn through that bending stage so that inevitably there arises tensile strain in the solidified shell. Orienting, e.g., straightening the casting in a bending stage exerts additionally tensile stress upon the inside of the casting and provides compressive stress upon the outside; whereby the terms inside and outside are taken with reference to the curved path of casting. It was found particularly that tensile strain resulting in the casting from the tensile stress may damage the casting. For example, there may appear transversely oriented cracks and fissures. However, if the casting, still having liquidous core, is positively driven immediately ahead of the first bending stage, the casting is less subjected to stress so that tensile strain in the casting adjacent the inside of the curved path is reduced, and damages of the casting can be avoided.

As compressive strain arises during orienting and straightening on the outside of the still curved path only, it is not of advantage to provide also driven rolls along on the outside. Moreover, if driven rolls are provided on the inside of the curved path, ahead of the bending stage, the straightening and orienting process in the bending point is considerably supported, because a driven roll engaging the casting tends to straighten the same.

By increasing the number of driven rolls, the transportation rolls proper are actually relieved, so that tensile strain is further reduced in the casting. This relief and distribution of driven rolls is of decisive importance for those types of continuous casting machines in which the extracted casting is guided along a curved path while still having a liquidous core with sequential straightened of the casting in one or several stages. The particular selected position of the driven rolls, in accordance with the invention, avoids damaging the shell of the casting through overloading it within the extracting, guiding and straightening path.

In addition to driving rolls at specified locations ahead of the bending points, the rolls located right at the bending points along the guiding and straightening path may likewise be driven. Moreover, it is of advantage to drive the rolls disposed ahead of the bending point, and arranged along the inside of the curved guiding path with a higher torque, than the rolls located right at the bending points. Generally, the torque of all driven rolls should exhibit declining tendency in the direction of casting extraction and withdrawing.

The first driven roll of the entire roll assembly should be provided at the inside of the curved guiding path in accordance with another feature of the invention at a distance of at least 4 meters from the surface level of the molten material in the casting mold.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:

The FIGURE illustrates somewhat schematically equipment for continuous casting with a curved guiding path for the extracted casting.

Proceeding to the detailed description of the drawing, there is illustrated somewhat schematically a mold 1 having a bottom opening for extracting and withdrawing a casting 2. The casting 2 is particularly extracted from the bottom of the mold along a curved path. The withdrawing and guiding path is defined by a plurality of rolls supported in a conventional manner in a frame which is not illustrated. The entire guiding path is comprised of several consecutive arcs of circles with respectively increasing radius in direction of casting withdrawal; the radii of these circles are denoted with reference characters r1, r2, r3 and r4.

As can be seen from the illustration of the particular continuous casting equipment, the curved casting with still partially liquidous core is stepwise straightened and veers into the horizontal. For guiding and straightening the partially solidified casting there are provided rolls whereby groups of rolls performing comparable functions are denoted by similar reference numeral, such as 3, 3', 3", 5 and 6. In order to distinguish idling rolls from power driven rolls, the latters are designated by an X. It is understood that these driven rolls are coupled to suitable driving equipment. The rolls 4 are the principle extraction and casting withdrawing rolls; they are driven and in effect draw the string-shaped casting out of the mold and pull it through the roll guiding system.

Rolls 3' are arranged at the particular bending points of the guiding path, on the outside thereof; they are likewise driven. In addition to the transportation rolls 4, there are further rolls provided as driven rolls, and these, in accordance with the invention, include rolls 5. They are placed ahead of the first bending point of the string guiding path where the radius of curvature of the path changes from r1, to r2. Rolls 5 are particularly placed on the inside of the curve thereof. The drawing shows two of the rolls ahead of the first bending point and on the inside of the curved path as being driven. In accordance with the general rule of the invention, at least one of these rolls should be driven.

In addition, rolls 6 may be driven. There is one each of these rolls placed immediately ahead of each of the other bending points, but likewise only at the inside of the curved path. As stated above, rolls 3, arranged at the bending points, are provided with a driving input whereby the torque transmitted upon them is smaller than the torque of rolls 5 and 6. Rolls 3" disposed also at the bending points but on the inside of the curved guiding path are shown as idlers; however, they could also be driven.

The embodiment illustrated refers particularly to a curved casting guiding system in which the casting string is straightened and veers into the horizontal while its core is still liquidous. However, the invention can also be employed in continuous casting equipment in which the string is guided along and into a particular curve, but still having liquidous core. In all these cases, however, it is of advantage that the first driven roll has minimum distance of 4 m. from the surface level of the molten material in mold l.

The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.

We claim:

1. In equipment for continuous casting, a casting string withdrawing system including a plurality of rolls arranged along a curved withdrawal path, the combination comprising, means including rolls of the plurality to provide change of curvature of the curved casting as withdrawn along the path, there being at least one bending point for straightening the casting; and

means for driving some of said plurality of rolls said means for driving being arranged so that the driven rolls above the first bending point are located only on the inside of the curved withdrawal path, the remaining rolls of the plurality being idlers including all rolls above the first bending point on the outside of the curved path. 2. In the equipment as in claim 1, there being only one or two driven rolls arranged above the first bending point.

3. In the equipment as in claim l, the first one of the driven rolls in direction of casting withdrawal being located at least 4 meters from the surface level of the mold included in the side of the curve, there being a driven roll at each bending point.

7. In the equipment as in claim 6, the rolls ahead of the bending points providing higher torque than the rolls at bending points.

8. In the equipment as in claim 1, the driven rolls of the plurality providing torque declining in direction of withdrawing. 

1. In equipment for continuous casting, a casting string withdrawing system including a plurality of rolls arranged along a curved withdrawal path, the combination comprising, means including rolls of the plurality to provide change of curvature of the curved casting as withdrawn along the path, there being at least one bending point for straightening the casting; and means for driving some of said plurality of rolls said means for driving being arranged so that the driven rolls above the first bending point are located only on the inside of the curved withdrawal path, the remaining rolls of the plurality being idlers including all rolls above the first bending point on the outside of the curved path.
 2. In the equipment as in claim 1, there being only one or two driven rolls arranged above the first bending point.
 3. In the equipment as in claim 1, the first one of the driven rolls in direction of casting withdrawal being located at least 4 meters from the surface level of the mold included in the equipment.
 4. In the equipment as in claim 1, there being at least one driven roll disposed ahead of each of plural bending points and at the inside of the curved path.
 5. In the equipment as in claim 4, there being a driven roll disposed in each of plural bending points.
 6. In the equipment as in claim 1, there being at least one driven roll ahead of each of plural bending points, on the inside of the curve, there being a driven roll at each bending point.
 7. In the equipment as in claim 6, the rolls ahead of the bending points providing higher torque than the rolls at bending points.
 8. In the equipment as in claim 1, the driven rolls of the plurality providing torque declining in direction of withdrawing. 